lib/spawn_faction_adddup2.c

   1 /* Copyright (C) 2000, 2009-2024 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   4    This file is free software: you can redistribute it and/or modify
   5    it under the terms of the GNU Lesser General Public License as
   6    published by the Free Software Foundation; either version 2.1 of the
   7    License, or (at your option) any later version.
   8
   9    This file is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12    GNU Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public License
  15    along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
  16
  17 #include <config.h>
  18
  19 /* Specification.  */
  20 #include <spawn.h>
  21
  22 #include <errno.h>
  23 #include <unistd.h>
  24
  25 #if !_LIBC
  26 # define __sysconf(open_max) getdtablesize ()
  27 #endif
  28
  29 #if REPLACE_POSIX_SPAWN
  30 # include "spawn_int.h"
  31 #endif
  32
  33 /* Add an action to FILE-ACTIONS which tells the implementation to call
  34    'dup2' for the given file descriptors during the 'spawn' call.  */
  35 int
  36 posix_spawn_file_actions_adddup2 (posix_spawn_file_actions_t *file_actions,
  37                                   int fd, int newfd)
  38 #undef posix_spawn_file_actions_adddup2
  39 {
  40   int maxfd = __sysconf (_SC_OPEN_MAX);
  41
  42   /* Test for the validity of the file descriptor.  */
  43   if (fd < 0 || newfd < 0 || fd >= maxfd || newfd >= maxfd)
  44     return EBADF;
  45
  46 #if !REPLACE_POSIX_SPAWN
  47   return posix_spawn_file_actions_adddup2 (file_actions, fd, newfd);
  48 #else
  49   /* Allocate more memory if needed.  */
  50   if (file_actions->_used == file_actions->_allocated
  51       && __posix_spawn_file_actions_realloc (file_actions) != 0)
  52     /* This can only mean we ran out of memory.  */
  53     return ENOMEM;
  54
  55   {
  56     struct __spawn_action *rec;
  57
  58     /* Add the new value.  */
  59     rec = &file_actions->_actions[file_actions->_used];
  60     rec->tag = spawn_do_dup2;
  61     rec->action.dup2_action.fd = fd;
  62     rec->action.dup2_action.newfd = newfd;
  63
  64     /* Account for the new entry.  */
  65     ++file_actions->_used;
  66
  67     return 0;
  68   }
  69 #endif
  70 }